LU-17015 obdclass: new primitives for upcall cache

LU-17015 obdclass: new primitives for upcall cache

This patch adds 2 new primitives to the upcall cache mechanism:
- upcall_cache_get_entry_raw: get a ref on an existing entry;
- upcall_cache_update_entry: modify expiry time and state of an entry.

Lustre-change: https://review.whamcloud.com/52389
Lustre-commit: 2ddb1d33245c23c4cafe64fb917323bdf567c81f

Test-Parameters: trivial
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I4825f09ae807abb52ebe0e24719dcd915e8c8aef
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/52497
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>